Is the aminoterminal propeptide of type III procollagen degraded in the liver? A study of type III procollagen peptide in serum during liver transplantation in pigs.

The aminoterminal propeptide of type III collagen was monitored in serum during liver transplantation in nine pigs. The aim was to investigate whether removal of the liver causes any changes in the serum concentration of the propeptide. Another connective tissue component, hyaluronan, a glycosaminoglycan known to be degraded in the liver endothelial cells, was also measured. Removal of the liver caused a significant increase in the concentration of the intact propeptide as well as of hyaluronan. Gel filtration confirmed the increase in the amount of intact propeptide. However, another large propeptide-related antigen, eluted near the void volume, appeared in the antigen profile during the anhepatic phase. This peak probably represents the propeptide still attached to the collagen molecule (pN collagen). The findings indicate that the liver is involved in the degradation of the propeptide and of larger propeptide-holding proteins.